Job satisfaction and turnover of the first group of rural-oriented tuition-waived medical students in Guangxi, China: a mixed-method study.

BACKGROUND: In 2010, China launched a rural-oriented tuition-waived medical education (RTME) programme to train more general practitioners (GPs) to meet the needs of the rural health workforce. Motivating and maintaining GPs is an important consideration for the shortage in the rural health workforce. This study aimed to investigate job satisfaction and turnover among the first group of rural-oriented tuition-waived medical students (RTMSs) who had completed a three-year compulsory service in Guangxi, as well as the factors affecting RTMSs turnover. METHODS: This study adopted a mixed-method approach. A quantitative survey of 129 RTMSs was analysed (81.6% response rate), and qualitative interviews were conducted with 30 stakeholders, including 18 RTMSs, six administrators of the County Health Bureau, and six administrators of township health centers (THCs). A t-test, chi-square test, Fisher's exact test, and logistic regression analysis were used to examine the quantitative data, and thematic analysis was used to analyse the qualitative data. RESULTS: Among the 129 participants, the turnover rate was high, with 103 RTMSs reporting turnover (79.84%). Interpersonal relationships scored the highest in job satisfaction (3.63 ± 0.64) among RTMSs, while working conditions were rated the lowest (2.61 ± 0.85). Marital status (odds ratio [OR] = 0.236, 95% confidence interval [95%CI] = 0.059-0.953, P = 0.043), only child status (OR = 8.660, 95%CI = 1.714-43.762, P = 0.009), and job return satisfaction (OR = 0.290, 95%CI = 0.090-0.942, P = 0.039) were significantly associated with turnover. Univariate analyses showed that income had a significant influence on turnover, but the relationship gone by multivariable; however it was deemed important in the qualitative study. Qualitative analysis revealed that turnover was influenced by the working atmosphere, effort-reward imbalance, professional competence, and opportunities for training and promotion. CONCLUSIONS: This study provides insights for the policymakers about the priority areas for retaining GPs in rural locations and provides reference values for the retention of GPs in other regions with a shortage of rural health workers. For RTMSs to continue providing services to rural areas, the government should improve their salaries, balance their income and workload, provide more opportunities for training and career promotion, and managers should recognise their efforts and create an optimistic working atmosphere.

Circ_0002295 facilitated myocardial fibrosis progression through the miR-1287/CXCR2 axis.

Myocardial fibrosis (MF) is involved in hypertension, myocardial infarction and heart failure. It has been reported that circular RNA (circRNA) is a key regulatory factor of MF progression. In this study, we revealed that circ_0002295 and CXCR2 were elevated, and miR-1287 was reduced in MF patients. Knockdown of circ_0002295 effectively suppressed the proliferation, migration and MF progression. Circ_0002295 was the molecular sponge of miR-12878, and miR-1287 inhibitor reversed the biological functions of circ_0002295 on the myocardial fibrosis. CXCR2 was a target gene of miR-1287, and CXCR2 silencing relieved the impacts of miR-1287 inhibitor on cardiac myofibroblasts. Circ_0002295 promoted MF progression by regulating the miR-1287/CXCR2 axis, providing a possible circRNA-targeted therapy for MF.

The Hippo Signaling Core Components YAP and TAZ as New Prognostic Factors in Lung Cancer.

Background: The Hippo pathway is an essential signaling cascade that regulates cell and organ growth. However, there is no consensus about (i) the expression levels of the Hippo signaling core components yes-associated protein (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ) in lung cancer, especially in small cell lung cancer (SCLC), or (ii) their association with the prognosis of patients with SCLC. Methods: We screened relevant articles and identified eligible studies in the PubMed, EMBASE, COCHRANE, and WanFang databases. A combined analysis was performed to investigate (i) the expression levels of the major effectors, YAP and TAZ, in lung cancer and its subsets and (ii) their prognostic role in lung cancer, especially in SCLC. Results: In total, 6 studies related to TAZ and 13 studies concerning YAP were enrolled in this meta-analysis. We found that high TAZ expression was significantly associated with poor overall survival (OS) of patients with non-small cell lung cancer (NSCLC) in the overall population [P h < 0.001, crude hazard ratio (HR) = 1.629, 95% CI = 1.199-2.214 for TAZ expression; P h = 0.029, adjusted HR = 2.127, 95% CI = 1.307-3.460 for TAZ], the Caucasian population (P h = 0.043, crude HR = 1.233, 95% CI = 1.030-1.477 for TAZ expression), and the Asian population (P h = 0.551, adjusted HR = 2.676, 95% CI = 1.798-3.982 for TAZ). Moreover, there was a significant negative association between YAP expression and an unsatisfactory survival of patients with lung cancer (P h = 0.327, crude HR = 1.652, 95% CI = 1.211-2.253 for YAP expression) and patients with NSCLC [disease-free survival (DFS): Ph = 0.693, crude HR = 2.562, 95% CI = 1.876-3.499 for YAP expression; Ph = 0.920, crude HR = 2.617, 95% CI = 1.690-4.052 for YAP-mRNA; OS: Ph = 0.878, crude HR = 1.777, 95% CI = 1.233-2.562 for YAP expression], especially in the Asian population (DFS: P h = 0.414, crude HR = 2.515, 95% CI = 1.755-3.063; OS: P h = 0.712, crude HR = 1.772, 95% CI = 1.214-2.587). However, no association was observed in the multivariate combined analysis. High YAP expression was significantly associated with short OS of patients with SCLC in our combined multivariate analysis in the Asian population (P h = 0.289, crude HR = 4.482, 95% CI = 2.182-9.209), but not with crude data (P h = 0.033, crude HR = 1.654, 95% CI = 0.434-6.300). Conclusion: The Hippo pathway is involved in carcinogenesis and progression of NSCLC and SCLC, and high expression levels of YAP and TAZ are independent and novel prognostic factors for lung cancer.

C-Reactive Protein Levels Predict Responses to PD-1 Inhibitors in Hepatocellular Carcinoma Patients.

Background: Serum C-reactive protein (CRP) is a biomarker of an acute inflammatory response and has been successfully used as a prognostic predictor for several malignancies. However, the clinicopathological significance of CRP levels in hepatocellular carcinoma (HCC) patients being treated with PD-1 inhibitors remains unclear. Methods: Serum CRP levels were measured for a total of 101 HCC patients that had been treated with PD-1 inhibitors from July 2018 to November 2019. The clinicopathological data was retrospectively analyzed to identify any clinical implications between CRP levels and responses to PD-1 inhibitors and patients' progression-free survival (PFS). Results: The median PFS was 8.87 months in the CRP-low subgroup and 3.67 months in the CRP-high subgroup (P = 0.009). Univariate and multivariate Cox regression analysis demonstrated that both serum CRP and AFP levels were independent risk factors for the PFS of HCC patients treated with PD-1 inhibitors (P < 0.05). Moreover, Cox regression analysis after Propensity Score Matching showed the similar results. A prognostic model combining CRP and AFP levels could significantly stratify HCC patients receiving PD-1 inhibitors into low-, intermediate-, and high-risk subgroups (P < 0.001). Patients in the risk subgroups reported similar overall response rates (P = 0.625) and significantly different disease control rates (low- vs. intermediate- vs. high-risk groups: 81.6% vs. 65.1% vs. 35%, respectively, P = 0.002). Conclusions: The results of this study support the association between high serum CRP levels with the response and PFS for HCC patients receiving PD-1 inhibitors. Furthermore, the levels of both CRP and AFP in an HCC patient before treatment initiation show great potential for determining the efficacy of PD-1 inhibitors.

Metformin, Macrophage Dysfunction and Atherosclerosis.

Metformin is one of the most widely prescribed hypoglycemic drugs and has the potential to treat many diseases. More and more evidence shows that metformin can regulate the function of macrophages in atherosclerosis, including reducing the differentiation of monocytes and inhibiting the inflammation, oxidative stress, polarization, foam cell formation and apoptosis of macrophages. The mechanisms by which metformin regulates the function of macrophages include AMPK, AMPK independent targets, NF-κB, ABCG5/8, Sirt1, FOXO1/FABP4 and HMGB1. On the basis of summarizing these studies, we further discussed the future research directions of metformin: single-cell RNA sequencing, neutrophil extracellular traps (NETs), epigenetic modification, and metformin-based combination drugs. In short, macrophages play an important role in a variety of diseases, and improving macrophage dysfunction may be an important mechanism for metformin to expand its pleiotropic pharmacological profile. In addition, the combination of metformin with other drugs that improve the function of macrophages (such as SGLT2 inhibitors, statins and IL-1ß inhibitors/monoclonal antibodies) may further enhance the pleiotropic therapeutic potential of metformin in conditions such as atherosclerosis, obesity, cancer, dementia and aging.

Silencing of the CrkL gene reverses the doxorubicin resistance of K562/ADR cells through regulating PI3K/Akt/MRP1 signaling.

BACKGROUND: Doxorubicin is a first-line chemotherapy agent on human myelogenous leukemia clinical treatment, but the development of chemoresistance has largely limited curative effect. In this study, we aimed to evaluate the biological function and molecular mechanisms of CrkL to Doxorubicin resistance. METHODS: Quantitative reverse transcription-PCR (qRT-PCR) assay was performed to examine the expression of CrkL in K562 and K562/ADR cells. The expression of CrkL was silenced through RNA interference technology. MTT assay and flow cytometry were performed to detect the proliferation inhibition and apoptosis rate after CrkL siRNA transfection. The protein expression changes of PI3K/AKT/MRP1 pathway induced by CrkL siRNA were observed by Western Blot assay. Xenograft tumor model was carried out to observe tumor growth in vivo. RESULTS: We observed that silencing of CrkL could effectively increase apoptosis rate induced by doxorubicin and dramatically reversed doxorubicin resistance in K562/ADR cells. Further studies revealed knockdown CrkL expression suppressed PI3K/Akt/MRP1 signaling, which indicated CrkL siRNA reversed doxorubicin effect through regulating PI3K/Akt/MRP1 pathway. In addition, overexpression of MRP1 could evidently reduce apoptosis rate and reversed the inhibitory effects of doxorubicin resistance caused by CrkL siRNA on K562/ADR cells. Finally, in vivo experiments revealed that CrkL silencing acted a tumor-suppressing role in myelogenous leukemia via regulating PI3K/Akt/MRP1 signaling. CONCLUSION: Together, we indicated that CrkL is up-regulated in myelogenous leukemia cells and silencing of CrkL could reverse Doxorubicin resistance effectively. These results show a potential novel strategy for intervention chemoresistance in myelogenous leukemia during chemotherapy.

Natural products: The role and mechanism in low-density lipoprotein oxidation and atherosclerosis.

Atherosclerosis is a chronic inflammatory, metabolic, and epigenetic disease, which leads to the life-threatening coronary artery disease. Emerging studies from bench to bedside have demonstrated the pivotal role of low-density lipoprotein (LDL) oxidation in the initiation and progression of atherosclerosis. This article hereby reviews oxidation mechanism of LDL, and the pro-atherogenic and biomarker role of oxidized LDL in atherosclerosis. We also review the pharmacological effects of several representative natural products (vitamin E, resveratrol, quercetin, probucol, tanshinone IIA, epigallocatechin gallate, and Lycopene) in protecting against LDL oxidation and atherosclerosis. Clinical and basic research supports the beneficial effects of these natural products in inhibiting LDL oxidation and preventing atherosclerosis, but the data are still controversial. This may be related to factors such as the population and the dosage and time of taking natural products involved in different studies. Understanding the mechanism of LDL oxidation and effect of oxidized LDL help researchers to find novel therapies against atherosclerosis.

SIRT3 inhibits cardiac hypertrophy by regulating PARP-1 activity.

Sirtuin 3 (SIRT3) is a type III histone deacetylase that inhibits cardiac hypertrophy. It is mainly localized in the mitochondria and is thus implicated in mitochondrial metabolism. Recent studies have shown that SIRT3 can also accumulate in the nuclear under stressed conditions, and participated in histone deacetylation of target proteins. Poly [ADP-ribose] polymerase 1 (PARP-1) functions as an important PARP isoform that was involved in cardiac hypertrophy. Our experiments showed that SIRT3 accumulated in the nuclear of cardiomyocytes treated with isoproterenol or SIRT3 overexpression. Moreover, overexpression of SIRT3 by adenovirus inhibited the expression of cardiac hypertrophic genes-ANF and BNP, as well as abrogating PARP-1 activation induced by isoproterenol or phenylephrine. In addition, co-immunoprecipitation experiments revealed that SIRT3 could interact with PARP-1, and overexpression of SIRT3 could decrease the acetylation level of PARP-1. Our results indicate that SIRT3 exerts protective effects against cardiac hypertrophy by reducing the level of acetylation and activity of PARP-1, thus providing novel mechanistic insights into SIRT3-mediated cardiprotective actions.

Cooperation of the ATM and Fanconi Anemia/BRCA Pathways in Double-Strand Break End Resection.

Cells deficient in ataxia telangiectasia mutated (ATM) are hypersensitive to ionizing radiation and other anti-cancer agents that induce double-strand DNA breaks. ATM inhibitors may therefore sensitize cancer cells to these agents. Some cancers may also have underlying genetic defects predisposing them to an ATM inhibitor monotherapy response. We have conducted a genome-wide CRISPR screen to identify genetic vulnerabilities that sensitize lung cancer cells to ATM inhibitors. Knockout of genes in the Fanconi anemia (FA)/BRCA pathway results in hypersensitivity to the ATM inhibitor M3541. Knockdown of either an FA gene or of ATM results in reduced double-strand break end resection, enhanced non-homologous end joining (NHEJ) repair, and decreased homologous recombination repair. Knockout of both the FA/BRCA pathway and ATM strongly inhibits end resection and generates toxic levels of NHEJ, thereby elucidating a mechanism of cellular death by synthetic lethality. ATM inhibitors may therefore be useful for the treatment of tumors with a defective FA/BRCA pathway.

Paeonol Suppresses Proliferation and Motility of Non-Small-Cell Lung Cancer Cells by Disrupting STAT3/NF-κB Signaling.

Background: Targeting inflammatory microenvironment is a promising anti-tumor strategy. Paeonol is a phenolic compound with effective anti-inflammatory and anti-tumor properties. However, the effects of paeonol on non-small cell carcinoma (NSCLC) have not been fully investigated. Here, we evaluated the effects of paeonol on proliferation and metastasis of NSCLC and elucidated the underlying mechanisms. Methods: The effects of paeonol on inflammatory cytokines were determined by cell proliferation and ELISA assays. Assays of wound healing, single cell migration and perforation invasion were used to evaluate migration and invasion of NSCLC cells. Expression of marker proteins in epithelial-mesenchymal transition (EMT) and matrix metalloproteinase (MMP) family enzymes were detected by Western blot assays. Nude mouse A549 cells transplantation tumor model was used to study the anti-lung cancer effects of paeonol in vivo. TUNEL stanining were used to detect the apoptosis of tumor cells in A549 lung cancer mice, and Ki67 analysis was used to detect the proliferation of tumor cells in A549 lung cancer mice. Immunohistochemistry was used to detect the effects of paeonol on signaling molecules in tumor tissues. Results: Paeonol inhibited A549 cancer cell migration and invasion in vitro. Paeonol inhibited secreaion of inflammatory cytokines in A549 cells, including tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-1ß, and transforming growth factor (TGF)-ß. Paeonol altered the expression of marker proteins involved in EMT and MMP family enzymes. In addition, paeonol inhibited the transcriptional activity of nuclear factor-κB (NF-κB) and phosphorylation of signal transducers and activators of transcription 3 (STAT3). Paeonol inhibited the growth of A549 cells transplanted tumors in nude mice. Conclusion: Paeonol potently inhibited NSCLC cell growth, migration and invasion associated with disruption of STAT3 and NF-κB pathways, suggesting that it could be a promising anti-metastatic candidate for tumor chemotherapy.

A novel splice mutation induces exon skipping of the EXT1 gene in patients with hereditary multiple exostoses.

The molecular mechanism of hereditary multiple exostoses (HME) remains ambiguous and a limited number of studies have investigated the pathogenic mechanism of mutations in patients with HME. In the present study, a novel heterozygous splice mutation (c.1284+2del) in exostosin glycosyltransferase 1 (EXT1) gene was identified in a three­generation family with HME. Bioinformatics and TA clone­sequencing indicated that the splice site mutation would result in exon 4 skipping. Reverse transcription­quantitative polymerase chain reaction (RT­qPCR) revealed that the expression levels of wild­type EXT1/EXT2 mRNA in patients with HME were significantly decreased, compared with normal control participants (P<0.05). Abnormal EXT1 transcript lacking exon 4 (EXT1­DEL) and full­length EXT1 mRNA (EXT1­FL) were overexpressed in 293­T cells and Cos­7 cells using lentivirus infection. RT­qPCR demonstrated that the expression level of EXT1­DEL was significantly increased, compared with EXT1­FL (17.032 vs. 6.309, respectively; P<0.05). The protein encoded by EXT1­DEL was detected by western blot analysis, and the level was increased, compared with EXT1­FL protein expression. Immunofluorescence indicated that the protein encoded by EXT1­DEL was located in the cytoplasm of Cos­7 cells, which was consistent with the localization of the EXT1­FL protein. In conclusion, the present study identified a novel splice mutation that causes exon 4 skipping during mRNA splicing and causes reduced expression of EXT1/EXT2. The mutation in EXT1­DEL generated a unique peptide that is located in the cytoplasm in vitro, and it expands the mutation spectrum and provides molecular genetic evidence for a novel pathogenic mechanism of HME.

Targeted Next-Generation Sequencing Newly Identifies Mutations in Exostosin-1 and Exostosin-2 Genes of Patients with Multiple Osteochondromas.

Multiple osteochondromas (MO) is one of the most common benign bone tumors in humans with an autosomal dominant hereditary mode. MO is a genetic heterogeneity disease with variable number and size of osteochondromas, as well as changeable number and location of diseased bones. Mutations in Exostosin-1/Exostosin-2 (EXT1/EXT2) genes are the main molecular basis of MO. EXT1 and EXT2 genes encode exostosin 1 and exostosin 2, respectively, both of which are transmembrane glycosyltransferases that elongate the chains of heparin sulfate (HS) at HS proteoglycans (HSPGs). HSPGs are considered to be involved in regulating the proliferation and differentiation of chondrocytes. Owing to large size of EXT1/EXT2 genes and lack of mutation hotspots, molecular diagnosis of MO is challenging. Here, we applied targeted next-generation sequencing (t-NGS) in mutation screening of EXT1/EXT2 genes for 10 MO patients. The results were compared and validated with Sanger sequencing. Overall, nine mutations identified by t-NGS were confirmed with Sanger sequencing, excluding two variants of false positive, suggesting the reliability of mutation screening by t-NGS. The nine mutations identified by t-NGS include two missense mutations (EXT1: c.1088G>A and c.2120C>T), one splicing mutation (EXT2: c.744-1G>T), and six nonsense mutations (EXT1: c.351C>G, c.1121G>A, and c.1843_1846dup; EXT2: c.67C>T, c.561delG, and c.575T>A). In summary, our paper provides the primary data of the application of t-NGS in MO molecular diagnosis, including six newly identified mutations (EXT1: c.1843_1846dup, c.1088G>A, c.351C>G, and c.2120C>T and EXT2: c.744-1G>T and c.575T>A), which further enrich the mutation database of MO from the Chinese population.

[Analysis of a multiple osteochondroma case caused by novel splice mutation (c.1164+1G to A) of EXT1 gene].

OBJECTIVE: To detect potential mutation of EXT1 gene in a pedigree affected with multiple osteochondroma and explore its pathogenic mechanism. METHODS: The coding regions and their flanking sequences of the EXT1/EXT2 genes were subjected to PCR amplification and Sanger sequencing. Suspected mutations were verified by excluding possible single nucleotide polymorphisms and bioinformatics analysis. Transcripts of the EXT1 gene in the proband were analyzed by TA clone-sequencing, with its abundance compared with that of healthy controls. RESULTS: DNA sequencing has identified in the proband a novel heterozygous point mutation (c.1164+1G to A) at the 5'splice sites of intron 3 of the EXT1 gene. The same mutation was not found in the healthy controls. Bioinformatics analysis indicated that the mutation is highly conserved and can lead to skipping of exon 3 or aberrant splicing. TA clone-sequencing indicated that the numbers of transcripts with skipping of exon 3 has significantly increased in the proband (< 0.05) compared with the controls. CONCLUSION: The c.1164+1G to A mutation has resulted in skipping of exon 3 in a proportion of EXT1 gene transcripts. As the result, the number of transcripts with tumor suppressing function is relatively reduced and has ultimately led to the tumors.

Genotype GG of rs895819 Functional Polymorphism Within miR-27a Might Increase Genetic Susceptibility to Colorectal Cancer in Han Chinese Population.

BACKGROUND: MicroRNA-27a (miR-27a) is supposed to be an oncogene in various types of cancers, and genetic variation of miR-27a might result in aberrant expression and abnormal second structure of mature-miR-27a, contributing to elevated genetic risk and poor prognosis for colorectal cancer (CRC). METHODS: In order to explore the possible association between rs895819 within miR-27a and CRC in Han Chinese population, we investigated the genotype distributions of rs895819 in 508 CRC cases and 562 healthy check-up controls using TaqMan genotype discrimination system, and analyzed the possible association between them. Odds ratio (OR) and 95% confidential interval (95% CI) were used to assess the strength between allele and genotype of the locus and risk of CRC. RESULTS: In our study, we found that genotype GG of rs895819 was significantly associated with an increased risk for CRC (17.1% vs. 11.6%, adjusted OR = 1.546, 95% CI = 1.070-2.236), and allele A carrier (AA/AG) was significantly associated with a decreased risk for CRC (82.9% vs. 89.4%, adjusted OR = 0.63, 95% CI = 0.446-0.893). In addition, a significant association was observed between genotype GG and larger tumor size (>5 cm; P < 0.001), and allele G was significantly associated with higher pathological stage (TNM-III) (P = 0.008). CONCLUSION: These results indicated that miR-27a might be involved in the development and progression of CRC, genotype GG within rs895819 might be a genetic susceptible factor for CRC. Further multicentral, large sample size, and well-designed epidemiological study as well as functional study are warrant to verify our findings.